Add enabled check to Column#isResizable (#12063)

client/src/main/java/com/vaadin/client/widgets/Grid.java

          *         otherwise
          */
         public boolean isResizable() {
-            return resizable;
+            return grid.isEnabled() && resizable;
         }
 
         /**
                 !enabled || editorOpen);
         getEscalator().setScrollLocked(Direction.HORIZONTAL, !enabled);
 
+        getHeader().requestSectionRefresh();
+
         fireEvent(new GridEnabledEvent(enabled));
     }